A planetary gear of the aforementioned type is already known in which the sun wheel is mounted in the planet wheel carrier which, for its part, provides a two-sided mounting for the planet wheel pins. This construction is complex and expensive to produce and as a result of the numerous bearings, entails fairly high friction losses.
Also known is a rotary blower or a rotary compressor incorporating a planetary gear (AT-PS No. 245 715). In this arrangement, one end of the impeller shaft is designed as a pinion and acts as the sun wheel of a planetary gear having helical gearing which has three or more planet wheels. These planet wheels rotate on the trunnions of a stationary planet wheel carrier. A hollow wheel with internal toothing is mounted only in toothed engagement with the planet wheels. Connection to an electric motor is achieved by way of a movable toothed clutch or gear coupling. In this respect one half of the toothed clutch is formed by the hollow wheel, whereas the other half of the toothed clutch is securely keyed onto the free end of the shaft of the electric motor. Thus there is considerable structural complexity and the bearings of the electric motor also have to be used to carry one half of the movable toothed clutch.
The object of the present invention is to provide a planetary gear of the type mentioned at the beginning which is simpler in construction and is more effective than known gears of this type.